Sound Meter FUN!

[LaLa661]

Hi Everyone,

This is a heads up that there will be some sound metering at upcoming Qualcomm events.

It has been a long time we had the sound meter out and it seems that perhaps some cars have gotten a little louder. So at the request of the Autocross Chairs, I have ordered a new digital, calibrated sound meter that will be used to measure car noise to make sure that we don't exceed our 92 db limit and get kicked out of Qualcomm.

I'm not sure yet how we intend to enforce this and what the rules of enforcement will be, as that is up to someone other than me, but for now, i'd like to at least monitor the noise so that people can be aware of where they stand on the db meter and adjust their cars accordingly. Sound ok? I will start taking measurements at the upcoming autocross this Saturday. Since theoretically no one knows how loud their car is, I will only monitor the noise and attempt to write down all cars that exceed the 92 db limit. As i'm only one person, this may prove difficult for every car...at a minimum, i'll try to monitor the cars that are suspected or rumored of being over the limit. If you're over the limit, i'll let you know...and I promise to be nice.

Here's how the measurements will be taken (this is in line with SCCA):
1. Measurement is taken at a point on the course where the car can reasonably be expected to be at full throttle, under load, and at high rpm.
2. Measurement is taken perpendicular to the course, 50 ft back from the track edge.

If you're wondering why i'm using SCCA rules, it's only because I couldn't find any provided by PCA so, I went to another source that autocross at the same place we do. If you have different ideas of how to do it, i'm open for discussion, but for now it seems easiest to use SCCA just so that there's some consistency between clubs.

I've heard rumors that perhaps the 92 db limit set by Qualcomm is for a distance greater than 50 ft -- I don't know anything about this but if someone has access to the contract that can check, that would be great.

I'm open to any and all comments on this and how to enforce. Love it? Hate it? Have a better way? Wanna go home and kick the cat? Wanna go home and kick me? Let me know!

Happy Racing!

...and sorry for the long post!

Lorri
lscheus@yahoo.com
equipment@pcasdr.org

[davidsq]

THATTA GIRL...

WE WILL KICK YOU LATER...
DQ

[MTrotter]

what do you think? after reviewing the rules.... placing the sound meeter just past "E3" sounds good to me. what do you think?

[pdy]

Poor Snickers...

I'd vote for H3

[Dan Chambers]

I seem to recall, back when Fred Flintstone and Barney Rubble drove for TTOD, that Greg Phillips used to be the "dB Monitor Man" at the Q. He'd set up the dB meter at a strategic spot and shoot pictures while monitoring the sound machine. Has anyone contacted Greg about his policies and practices? He might provide some insight into the old PCASDR noise monitoring policy at the Q.

Greg, you out there?

[ttweed]

I've heard rumors that perhaps the 92 db limit set by Qualcomm is for a distance greater than 50 ft -- I don't know anything about this but if someone has access to the contract that can check, that would be great.

Lorri-
I don't know about the limitations set in the contract with Qualcomm, but I do know that SCCA uses a 93 db limit @ 50', not 92. I think we set our limit 1 db lower to give us a margin of error on the readings (which should be taken on the "A" scale under "slow" response). They start warning people immediately in the grid who register 91 db or higher, and anyone who exceeds 93 db must make an immediate effort to reduce sound levels before taking another run. From their supplemental regs: "Physical changes to the vehicle that result in a drop in the noise output of the vehicle are the only accepted means of compliance." This means you can't just lift off the throttle in the measurement zone to reduce the noise. Three runs above 93 db (after attempting mods) and you are DQ'd from the event. Any single run exceeding 99 db is grounds for immediate DQ.

TT

[John Straub]

Back when the earth was still cooling I worked as the Sound Meter Chair for several years...this was before Barney Rubble was rocketing to TTOD. We just warned people to try to fix it before they could go back out on the track. It also has a lot to do with which direction the meter was pointed and if there was cloud cover. Some days a car would be over and some days the same car would not.

Needless to say...this was not very popular with the offenders.

We did lose a few competitors over those years, so we started to relax the monitoring of cars. To my recollection we as a club only had one complaint for noise. That is what started us to do the checking in the first place. If I remember that started back in the 90s.

John

[Greg Phillips]

I've heard rumors that perhaps the 92 db limit set by Qualcomm is for a distance greater than 50 ft -- I don't know anything about this but if someone has access to the contract that can check, that would be great.

Lorri-
I don't know about the limitations set in the contract with Qualcomm, but I do know that SCCA uses a 93 db limit @ 50', not 92. I think we set our limit 1 db lower to give us a margin of error on the readings (which should be taken on the "A" scale under "slow" response). They start warning people immediately in the grid who register 91 db or higher, and anyone who exceeds 93 db must make an immediate effort to reduce sound levels before taking another run. From their supplemental regs: "Physical changes to the vehicle that result in a drop in the noise output of the vehicle are the only accepted means of compliance." This means you can't just lift off the throttle in the measurement zone to reduce the noise. Three runs above 93 db (after attempting mods) and you are DQ'd from the event. Any single run exceeding 99 db is grounds for immediate DQ.

TT

Yes it has been a few years since my days as Noise chair.
We did use the Radio Shack noise meter, first an analog and later the digital device. I think we still have the analog in the trailer. I would use it on the dB A scale with slow response and mounted on tripod at full height pointed up at 45 degrees. I would pick a spot where drivers would be on the throttle to take the readings.
I think if we are going back to more frequent sound checks it would best be handled through the corner work chairs as another corner work task (like the gate). Set up the meter and have someone monitor the meter instead of corner working.
Not sure of the motivation for restarting the monitoring. We were having some complaints from the condos up on the hill in the past (when Rich Caccese was president) which was the motivation for setting up a noise chair.

Greg

[John Straub]

Yep...pointed up at 45 and about 50 ft. And not pointed at the Stadium buy rather at open space.

John

[Kim Crosser]

Not sure of the motivation for restarting the monitoring.

At the last AX, there were around 10 cars that didn't just nudge the 92 dB limit, they crushed it - I think the "winner" was up around 110 dB.

For some of the cars, those of us trying to do timing in the trailer had to wait until the car had gotten a ways down the track before anything else could be heard (like cone calls, etc.).
Clearly, if the noise is excessive to us, it is just a matter of time before we start getting noise complaints from the neighbors.

Rather than wait for the Stadium to tell us we are breaking the rules, we are trying to bring the levels back down to the stated limits.
110 dB(A) is over 3x "louder" than 92 dB(A), and if we don't rein in some of the excessively loud cars, I am sure we will be getting notice from the Stadium soon.

[Bill Behun]

OK. Here we go and thank you Kim for your introduction to this issue.

I set up our analog sound meter at the last AX per Steve Grosekempers "specs" - 50 feet perendicular from the track edge, on a tripod and aimed not 45 degrees up but 45 degrees to the direction the car is driving to. I didn't get everybody but we were curious what the results might indicate.

The "official" results are: (Let's see, it was a D&G AX - and the winners are????? OCR )

Car db
Herb & Sean = 98+ many times
Steve Equina = 106,108 many times
Jackie Corwin = 94+/96
Robert Schuessler = 102/106
Adam Gill = 92.5
Rusell Shon = 96+/98
Morgan Trotter = 98+
Tom Tweed = 96+/100
Don Middleton = 92.5/96
Doug Wierenga = 96+/97
Kelsey Malmberg= 92.5
Doug Hansen = 92.5
Radomin Delgado = 93
Steve Groskemper = 92
Even Fullerton = 94/92/94
Tawfik = 96+/100
Paul Young = 93/92/93
Gunter Enz = 94 (really?)
Mark Matsumoto = 92 (mr. 928)
Tom Comeau = 102
Mario Monroy = 94
Derek Whitacre = 93/96+/98

[LaLa661]

It seems that everyone is in agreement on how to set the meter for the readings (A and slow) but there is not a consensus on how to orient the meter. The measurement is taken 50 ft from the track edge, perpendicular to the direction of the vehicle --- so there's no setting the meter sideways at a 45 degree angle. I'm also not sure on angling the meter 45 degrees upward as I don't see anything in written about that. In the limited times i've sat at the sound meter for SCCA, I don't remember the meter being angled that way, but maybe my memory fails me. We can experiment with that this weekend and see how it changes the results -- maybe it won't make a big difference...or maybe it will...we'll see i guess.

As for the readings we took from the last event, I don't think they can be considered wholly accurate as they were not measured in the way that is intended. Tomorrow, readings will be taken from E3 and anyone close to 92 db will be notified.

I'll make sure to label the sound meter with how to set it up (A and slow) so that someone new to it will know what to do. Also, the calibrator is REALLY easy to use and the instructions are included in the kit (not that anyone reads instructions anyhow). I would recommend calibrating before each event -- it only takes a couple minutes.

See you all tomorrow!

[Kim Crosser]

John Straub's note about not pointing at the Stadium is a good one. If the meter is highly directional, it should be pointed at open space if possible. If pointed at the Stadium, it will be picking up reflected sound, which will affect the overall Sound Pressure Level (SPL or dBA measurement).
If there are two equal sound sources (say 2 90 dBA cars at roughly equal distance from the meter), combined they will add 3 dBA, resulting in a 93 dbA measurement. Multiple acoustic reflections can easily cause readings to be too high.

[Gunter]

So you measured me at 94??!!How?
Laguna Seca measured me at 90.8 two years in a row with the exact same exhaust.The limit up there is 92. Don't know how you get 94.
Since this is not a stadium rule(or is it?) why do we have a noise restriction of 92 50 feet from the track??? Who the heck do we bother 50 feet from the track??
The next condo is -what-1000 feet. I am missing something here
Since my exhaust passed Laguna I certainly would not and will not spend a penny to meet this AX requirement.
In guess my Spec did not pass either ...wow! Two cars on the "Bad Boy" list...

[rshon]

98 dB? I don't think so. When you see my in-car videos at the track, the exhaust sound from my engine gets drowned out by the surrounding race cars (including the 944's). I think we need to calibrate the loose nut behind the sound meter...